§first trimester · week 5 of 40
you're 5 weeks pregnant.
last revised · baby is about 0.2 cm (0.08") · 0.1 g (0.00 oz)
about the size of a chia.
Tiny but mighty — your baby's tube-like heart is beating for the first time, even though you can't feel it yet.
this week's highlights
- First heartbeats
- Neural tube closes
- Blood vessels form
- Hormones surge in you
how your baby looks
A curved C-shape with a distinct head end and tail end. The heart is a tiny pulsing tube, visible on a high-resolution ultrasound by the end of next week.
body in focus
- head
- Neural tube closes — the foundation of the brain and spinal cord is in place.
- body
- The heart tube starts pulsing — the very first heartbeats.
- hands
- feet
what's happening in your body
HCG is climbing quickly. Many people feel breast tenderness, fatigue, food aversions, or a metallic taste in the mouth. Early nausea can start anytime now.
gentle tips
- Eat small frequent meals to keep nausea away.
- Sip water steadily — dehydration makes nausea worse.
- Take your prenatal vitamin at night with food if it upsets your stomach.
- Rest when you can — first-trimester fatigue is no joke.
- Avoid changing cat litter to reduce toxoplasmosis risk.
what to expect next
Arm and leg buds appear next week, and the embryo starts to look more like a tiny shrimp than a disc.